(I don't own the Angry Marines, I'm writing this blog for non-canon reasons.)
Angry Marines are non-canon Chapter who are shown to be very angry and foul mouthed.
Origins[]
The Angry Marines are basically a meme from 4chan as an extreme Space Marine chapter, most pictures show the using "non-conventional" weapons such as a rocket launcher that launches Angry Marines. Angry Marines are represented holding their middle finger and violent.
Appearance[]
Their banner is usually an angry yellow face with swear words and other words on it or it is the "This is Sparta!!!" Meme.
Trivia[]
They appear in the Dark Crusade mod "Firestorm over Kronus.